/Engine/Source/Runtime/Engine/Public/PacketHandlers/StatelessConnectHandlerComponent.h
The different handshake protocol versions
namespace UE { namespace Net { enum EHandshakeVersion { Original = 0, Randomized = 1, NetCLVersion = 2, SessionClientId = 3, NetCLUpgradeMessage = 4, Latest = NetCLUpgradeMessage, } } }